The present application relates generally to weather detection and prediction. More particularly, the present application relates to the detection of and the growth prediction of storm tops.
Thunderstorms are a violent example of atmospheric convection with the uplift and cooling of air and subsequent cloud formation. As the cloud forms, water vapour changes to liquid and/or to frozen cloud particles resulting in a large release of heat that becomes the principal source of energy for the developing cloud. The cloud particles grow by colliding and combining with each other, forming rain, snow, and/or hail. High level winds may shear the cloud top into an anvil shape. When the droplets become heavy enough to fall against the updraft created as the cloud forms, precipitation begins. Once precipitation begins the updraft which initiated the cloud's growth weakens and is joined by a downdraft generated by the precipitation. This updraft-downdraft couplet constitutes a single storm cell. A typical storm is composed of multiple cells that form, survive for about half an hour, and then weaken and disperse. In some circumstances, new cells may replace old ones making it possible for some storms to continue for up to several hours.
Storm tops are hazards to aircraft. Conventionally, pilots use weather radar to detect and then avoid hazardous weather. Effectively and efficiently identifying and predicting storm tops using a weather radar is very beneficial for pilots that need to fly over the storm cell to avoid the hazardous weather. Meteorological radars are capable of detecting precipitation and variations of the refractive index in the atmosphere that may be generated by local variations of temperature or of humidity. The returned signal from the transmitted pulse encountering a weather target has an amplitude, a phase, and a polarization. The amplitude is used to determine the reflectivity and to estimate the mass of precipitation per unit volume or the intensity of precipitation through the use of empirical relations.
In general, modern weather radars automatically perform a volume scan consisting of a series of full azimuth rotations of the antenna at several elevation angles. The raw polar data may be stored in a three-dimensional array for further data processing and archiving. Using application software, a wide variety of meteorological products may be generated and displayed as images on a display. Grid or pixel values and conversion to x-y coordinates are computed using three-dimensional interpolation techniques. Each image pixel represents a color-coded value of a selected variable such as the reflectivity, the rainfall rate, etc. Vertically-integrated liquid can be displayed for any specified layer of the atmosphere as an indicator of the intensity of severe storms.
Turbulence is the leading cause of in-flight injuries to passengers and cabin crews on aircraft. A high turbulence region exists above a storm cell, but is difficult to detect with radar due to the low reflectivity. However, if a weather radar system can detect and predict the location of the high turbulence region with sufficient response time, aircraft can successfully avoid storm system hazards. Thus, there is a need for a system and a method for efficiently detecting the height of a storm cell. What is further needed is a system and a method to predict the change in the height of the storm cell for a forecast time period so that the aircraft can better respond to the changing conditions.